DE102016224296A1 - ELECTRIC HEATING DEVICE - Google Patents

Abstract

The present invention relates to a PTC heating element (40) with a heating element housing (134) which has at least one PTC element (120) and contact plates (128) energizing the PTC element (120) and forming contact tongues (42) for an electrical plug connection. for the electrical connection of electrically connected to the PTC element (120) connected electrodes (130) as a structural unit, wherein the PTC element (120) is covered at least at one of its two major side surfaces (122) with an insulating layer (124). An inexpensive to produce PTC heating element (40) is characterized in that the Heizelementgehäuse has an injection-molded plastic frame (134) which surrounds the insulating plate (124) only at the edge and defines opposite frame openings (136), behind which the PTC element (120) with its major side surfaces (122) exposed.

Description

The present invention relates to a PTC heating element with a heating element housing which adds at least one PTC element and the PTC element energizing and contact tongues for an electrical connector forming contact plates for the electrical connection of electrically connected to the PTC element electrodes as a structural unit. Such a PTC heating element is for example from the EP 2 607 121 A1 known. This prior art PTC element is the PTC heating element of an air heater. In a housing frame forming the heating element housing a plurality of PTC elements are received, which are contacted on opposite main side surfaces with a contact plate, which are locked to the position frame. On one end side, the heating element housing is surmounted by connecting pieces, which are integrally formed on the heating element housing and over which sealing sleeves made of Teflon are drawn with a provided on the outer peripheral surface labyrinth seal. On the side facing away from the PTC elements outer side of the contact sheets each insulating layers are applied, which are formed of a plastic film.

From the EP 1 253 808 A1 respectively. EP 1 395 098 A1 Similar PTC heating elements are known. In this prior art, the contact plate is at least on one side encapsulated together with the insulating layer in the manufacture of the Heizelementgehäuses, so that only the PTC elements are inserted into the opening of the frame-shaped Heizelementgehäuses and to cover on the opposite side with the contact plate and the insulation.

Although such an embodiment is compared to the prior art described above a simplification in terms of production. However, the structure is still relatively expansive and consuming. The present invention intends to specify a PTC element, in particular for the motor vehicle industry. In motor vehicles, especially in the field of electromobility, increasingly PTC heating elements are used. These must be inexpensive to produce and be as light as possible. Furthermore, a good heat extraction of the heat generated by the PTC element is desired because the PTC elements have self-regulating properties and can only be operated with poor efficiency if the heat generated by the PTC element is dissipated insufficiently.

In view of this, the present invention proposes to form the heating element housing by an injection-molded plastic frame, which surrounds the insulation plate only at the edge. The plastic frame forms mutually opposite frame openings and surrounds the insulation plate and preferably a very narrow edge region of the PTC element, but does not completely cover the PTC element. Behind the frame openings defined by the plastic frame, the PTC element is exposed rather with its main side surfaces. It goes without saying that in the present case the PTC element is entirely or predominantly covered on its main side surfaces, regularly covering the PTC element on all sides by the insulation layer.

The PTC heating element according to the invention can be energized in a conventional manner. In this case lie on the opposite main side surfaces of the PTC element sheet metal strips, which preferably form the contact tongues of the electrical connector in one piece. The contact plates can cover all or part of the main side surface of the PTC element.

The injection molded position frame is usually made by overmolding the insulation plates with the PTC element disposed between the insulation plates. Thus, the plastic frame is material and / or positively connected to the insulation plate and the at least one PTC element between the two insulation plates. The plastic frame is preferably formed as a one-piece component. The plastic frame preferably defines the outer circumferential surface of the PTC heating element, which projects beyond the two contact tongues only on a predetermined side. This side is the connection side of the PTC heating element for connection to a control or connection board. On this side, the plastic frame by the frame material itself form a plug-in element, preferably the male plug element of a plug connection. The plug element is designed so that the PTC element can be mechanically fastened in a plug element receptacle, i. the attachment of the PTC element is also effected in the insertion direction solely by the design of the heater housing. Thus, the PTC element alone due to the connector in a holder of the connector, such as a partition, which separates a circulation chamber from a connection chamber, be held. The plastic frame may be formed of silicone.

In order to form this connector as fluid-tight as possible and also with regard to a good seal and sealing of the PTC element within the Heizelementgehäuses the plastic frame is formed of an elastomeric plastic according to a preferred embodiment of the present invention. This plastic is preferably not a TPE but a crosslinking elastomer. Due to the elasticity of the elastomeric plastic, the Plug connection are formed so that good holding forces result and further a solid example, liquid-tight seal in the region of the connector is generated.

In the solution according to the invention, the insulating layer is preferably applied directly to the PTC element or is applied directly thereafter, for example as a coating. Compared to the prior art according to EP 2 607 121 A1 Accordingly, the electrical supply of the PTC element takes place mainly or predominantly via the end face, ie via mutually opposite edges of the PTC element, which usually extend at right angles to the main extension direction of the insulation plate.

In this preferred embodiment, the insulating layers are preferably exposed in opposite frame openings, i. together with the material of the plastic frame form the outer surface of the PTC heating element. The two main side surfaces of the at least one PTC element within the Heizelementgehäuses are covered with this insulating plate and are preferably directly on it.

The insulating layers may be formed of a single- or multi-layer insulating plate which covers substantially the entire major side surface of the PTC element, covering it regularly, i. at least one side, preferably multi-sided and particularly preferably fully extends beyond the PTC element. The insulating layer can be formed for example by a combination of a ceramic plate with a plastic plate. However, the insulating layer may also be formed, for example, by coating the PCT element with an electrically insulating material. In this case, the PTC element forms the substrate, and the outer surface of the insulating layer is usually exposed within the plastic frame, so that there is a good heat dissipation of the heat generated by the PCT element. As a coating, for example, a ceramic coating in question, which is applied by means of PVD or CVD on the PTC element as Subtrat. An insulating layer applied as an insulating coating on the main side surface of the PTC element can be combined with an insulating plate of ceramic and / or plastic.

The energization of the at least one PTC element is carried out in a conventional manner preferably via a metal strip. This forms as a one-piece component both the contact tongue, as well as the electrically connected to the PTC electrode. This electrode is usually not the metallization deposited by PVD or CVD on the surface of the PTC element and adhered thereto. This is part of the PTC element. For contacting the sheet metal strip has an electrically conductive and applied to the PTC element contact web, which is usually extended in the longitudinal direction of the contact web by the contact tongue, which projects beyond the Heizelementgehäuse outside. All other parts of the PTC element are either sealed by encapsulating the plastic or provided within the frame opening.

To produce the PTC element according to the present invention, the metal strip is preferably adhesively bonded to the PTC element on opposite edge surfaces. It can also be glued several PTC elements with the metal strip in this way. The PTC elements can be provided at a distance from each other to avoid overheating in the central region of the PTC heating element. The sheet metal strip but at least in the region of the web has a slightly smaller thickness than the PTC element. Prepared in this way, an insulating plate is placed on opposite major side surfaces of the PTC element (s).

The insulating layer is or preferably comprises an insulating plate, for example a ceramic plate, since this has a relatively good thermal conductivity. The insulation plate is preferably placed so that this projects over the PTC elements or the entire circumference and at those locations where the sheet metal strip is, this partially covers. The insulating plate can be adhesively bonded to the metal strip and / or the PTC element. The thus prepared unit is placed in an injection mold, in the mold cavity, the main side surfaces of the insulation plate are clamped substantially between the mold halves. Only one edge region for the formation of the plastic frame remains circumferentially around the PTC element and the metal strip free as a circumferential annular channel. In this annular channel then plastic, preferably elastomeric plastic is injected, which crosslinks and thus hardens or abbbindet. After a sufficient dimensional stability of the plastic is achieved, the finished product is removed from the injection mold. For the gentle sealing of the main side surfaces of the insulating plate, the injection mold in the closed state with the insulating plate having cooperating surfaces which are formed of a soft, preferably soft elastic material, such as a thermoset. The injection molding of the plastic frame forming material takes place at relatively low pressures.

According to a preferred embodiment of the present invention, the plastic frame is provided on its outer side with a tapered contact web. This contact bar is in the thickness direction the plastic frame tapers. The contact bar is usually provided at least on a frame rail of the plastic frame. Particularly preferably, the contact web is provided on three successive outer sides or frame members of the plastic frame. At the contact surfaces opposite side of the plastic frame of the lower side of the support web forms a seal against the bottom of a heater housing. At right angles to the edge-side abutment webs serve to seal against a side wall of the heater housing. Thus, the PTC elements may be provided alternately offset, so that each first PTC heating element at one, for example, left side abuts against the heater housing, whereas each second PTC heating element is applied to the opposite, right housing wall. This is formed in a simple manner meandering flow channel. The edges of the system contact the PTC heating element with respect to the heater housing. The contact web is preferably formed in one piece, ie integral part of the injection-molded plastic frame. In particular, the lower contact web can also be used as a compression element to secure after installation of the PTC heating element according to the invention in the heater housing a certain mounting position by elastic biasing force. This fuse can be a mechanical fuse to mechanically fix the PTC heater to the heater housing. The biasing force can also or additionally provide for a reliable contacting of the contact tongues by biasing the PTC heating element.

The present invention offers the possibility of economically producing a PTC heating element by premounting the contact tongues together with the electrodes and the at least one PTC element and covering them with insulation plates on opposite main side surfaces of the PTC element into an injection mold in which the plastic frame is trained. This is preferably formed by an elastomer, so that the plastic frame can also form sealing means for a plug connection, preferably male plug element is formed by the PTC heating element itself. The elastomeric plastic also has the advantage that the plastic frame seals the insulating plate and optionally the metal strips for energizing the PTC elements or permanently elastic. Since the insulation plate preferably abuts directly on the PTC element and accordingly the energization of the PTC element takes place on the front side, the heat generated by the PTC element is coupled out in the best possible way. The PTC heating element is light. It can be produced economically.

The PTC heating element of the present invention is in particular a PTC heating element for a water heater, as it is known for example from the EP 2 797 381 A1 is known and which has a circulation chamber, which is fluid-tight in particular waterproof and can circulate in the liquid to be heated, which is separated via a partition wall of a connection chamber in which the contact tongues of the PTC heating element exposed. Preferably, a plurality of PTC heating elements are provided as part of this electrical heating device. By the choice of elastomeric plastic to form the plastic frame, the PTC heating element according to the invention can be inserted into the partition wall to arrange the contact tongues in the connection chamber and seal the circulation chamber due to the connector relative to the connection chamber. The connector also allows a holder of the PTC heating element in the insertion direction, so that the partition can be initially equipped with all PTC heating elements to handle the preassembled unit and finally close the heater housing, including the PTC or the heating elements.

The present invention further relates to an electric heater having a plurality of arranged in a circulation chamber PTC heating elements with a Heizelementgehäuse that adds at least one PTC element and the PTC element energizing and contact blades for an electrical connector forming contact sheets as a structural unit, and with a partition separating the circulation chamber from a connection chamber in which the contact wall of the PTC heating element projecting through the partition is exposed and electrically connected. Such an electric heater is for example from the EP 2 607 121 A1 known. This electric heater is designed as an air heater.

Generically, however, can also be attributed to the applicant EP 2 440 004 A1 which discloses an electric heater for heating a liquid medium. In the specific description, a heating element housing is disclosed, which as such EP 1 921 896 A1 is known and in the electric heater according to EP 2 440 004 A1 is installed.

In particular, the present invention relates to an electric heating device for a motor vehicle. Such components have always been weight-optimized. Furthermore, owing to the high quantities in the motor vehicle industry, economic manufacturability must be ensured. In electrical heaters with PTC heating elements further refinements are to be preferred, the most direct and allow symmetrical heat dissipation of the heat generated in the PTC element.

The present invention is based on the problem to provide an electric heater and a PTC heating element for such an electric heater, which can be produced economically.

1. 1. Elektrische Heizvorrichtung mit mehreren in einer Zirkulationskammer (62) angeordneten PTC-Heizelementen (40) mit einem Heizelementgehäuse (134), das zumindest ein PTC-Element (120) und das PTC-Element bestromende und Kontaktzungen (42) für eine elektrische Steckverbindung ausformende Kontaktbleche (128) als bauliche Einheit fügt, und mit einer Trennwand (54), die die Zirkulationskammer (62) von einer Anschlusskammer (56) trennt, in der die die Trennwand (54) durchragenden Kontaktzungen (42) des PTC-Heizelementes (40) freiliegen und elektrisch angeschlossen sind, gekennzeichnet durch eine zwischen der Trennwand (54) und dem PTC-Heizelement (40) ausgebildete Steckverbindung, über welche das PTC-Heizelement (40) in Steckrichtung reib- und/oder formschlüssig an der Trennwand (54) gehalten ist.
2. 2. Elektrische Heizvorrichtung nach Anspruch 1, gekennzeichnet durch der Steckverbindung zugeordnete Dichtungsmittel, durch die das PTC-Heizelement (40) gegenüber der Trennwand (54) fluiddicht abgedichtet ist.
3. 3. Elektrische Heizvorrichtung nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass das PTC-Heizelement (40) das männliche Steckelement und die Trennwand (54) das weibliche Steckelement der Steckverbindung ausbildet und dass das PTC-Heizelement (40) einen die Kontaktbleche (128) umgebenden weichelastischen Dichtkragen (48) ausbildet, der in einer Steckaufnahme (44) der Trennwand (54) dichtend eingepresst ist, so dass das PTC-Heizelement (40) reibschlüssig an der Trennwand (54) gehalten ist.
4. 4. PTC-Heizelement für eine elektrische Heizvorrichtung nach einem der vorherigen Ansprüche, wobei das PTC-Heizelement (40) ein Heizelementgehäuse (134) hat, das zumindest ein PTC-Element (120) und das PTC-Element (120) bestromende Kontaktzungen (42) für den elektrischen Anschluss von elektrisch mit dem PTC-Element (120) verbundenen Leiterbahnen (128) als bauliche Einheit fügt, dadurch gekennzeichnet, dass das Heizelementgehäuse (134) durch ein Elastomer gebildet ist, welches das wenigstens eine PTC-Element (120) umfänglich einsiegelnd umschließt.
5. 5. PTC-Heizelement nach Anspruch 4, dadurch gekennzeichnet, dass das Elastomermaterial einen die Kontaktzungen (42) umfänglich umsiegelnden Dichtkragen (48) ausbildet, der als Steckverbindung für die Halterung des PTC-Heizelementes (40) angepasst ausgebildet ist.
6. 6. PTC-Heizelement nach Anspruch 5, dadurch gekennzeichnet, dass der Dichtkragen (48) in Richtung auf die freien Enden der Kontaktzungen (42) konisch zulaufend ausgebildet ist.
7. 7. PTC-Heizelement einem der Ansprüche 4 bis 6, dadurch gekennzeichnet, dass das Heizelementgehäuse (134) als die Kontaktbleche (128) und das wenigstens eine PTC-Element (120) lediglich umfänglich fassender Rahmen (134) ausgebildet ist.
8. 8. PTC-Heizelement nach Anspruch 7, dadurch gekennzeichnet, dass der Rahmen (134) eine Rahmendicke hat, die nicht größer als 0,5 der größten Dicke des Dichtkragens (48) ist.
9. 9. PTC-Heizelement einem der Ansprüche 4 bis 8, dadurch gekennzeichnet, dass einander gegenüberliegende Hauptseitenflächen des PTC-Elementes (120) nicht mit dem Elastomermaterial belegt sind.
10. 10. PTC-Heizelement nach einem der Ansprüche 4 bis 9, dadurch gekennzeichnet, dass einander gegenüberliegende Hauptseitenflächen (122) des zumindest einen PTC-Elementes (120) ganz überwiegend nicht mit einem Kontaktblech belegt sind.
11. 11. PTC-Heizelement nach einem der Ansprüche 4 bis 10, gekennzeichnet durch eine Isolierlage (124), die unmittelbar an einer Hauptseitenfläche (122) des PTC-Elementes (120) wärmeleitend angelegt ist bzw. darauf vorgesehen ist.
12. 12. PTC-Heizelement nach einem der Ansprüche 4 bis 11, gekennzeichnet durch die Elektroden bildende Blechstreifen (128), die jeweils einen stirnseitig an dem PTC-Element (120) anliegenden Kontaktsteg (130) und die Kontaktzunge (42) ausbilden, die gegenüber dem Kontaktsteg (130) in der Breitenebene des PTC-Elements (120) verbreitetert ist.
13. 13. PTC-Heizelement nach Anspruch 12, dadurch gekennzeichnet, dass der Blechstreifen (128) an gegenüberliegenden Stirnseitenflächen (126) des PTC-Elementes (120) elektrisch leitend angeklebt sind.
14. 14. Gehäuse (22; 50) einer als Flüssigkeitsheizer ausgebildeten elektrischen Heizvorrichtung mit einer Anschlusskammer (56) und einer von einem zu erwärmenden Medium durchströmbaren Zirkulationskammer (14), wobei die beiden Kammern (56; 14) von einer durch das Gehäuse (22; 50) ausgebildeten Trennwand (54) aus Kunststoff voneinander getrennt sind, die zumindest eine Durchtrittsöffnung (46) für Kontaktzungen (42) eines in der Zirkulationskammer (14) anzuordnenden PTC-Heizelementes (40) aufweist, die in der Anschlusskammer (56) elektrisch an eine Bestromung des PTC-Elementes (120) bewirkende Leitungsbahnen anzuschließen sind, dadurch gekennzeichnet, dass die Trennwand (54) ein weibliches Steckelement (44) einer das PTC-Heizelement (120) in Steckrichtung reib- und/oder formschlüssig haltenden Steckverbindung ausgebildet ist.

To solve the first aspect, the following is proposed:

1. An electric heating device having a plurality of PTC heating elements (40) arranged in a circulation chamber (62) with a heating element housing (134), the at least one PTC element (120) and the PTC element energizing and contact tongues (42) for an electrical plug connection forming forming contact plates (128) as a structural unit, and with a partition wall (54) which separates the circulation chamber (62) from a connection chamber (56) in which the separating wall (54) protruding contact tongues (42) of the PTC heating element ( 40) are exposed and are electrically connected, characterized by a between the partition (54) and the PTC heating element (40) formed via which the PTC heating element (40) in the insertion direction frictionally and / or positively on the partition (54 ) is held.
2. 2. Electric heating device according to claim 1, characterized by the connector associated sealing means by which the PTC heating element (40) relative to the partition wall (54) is sealed fluid-tight.
3. 3. Electric heating device according to claim 1 or 2, characterized in that the PTC heating element (40) the male plug element and the partition (54) forms the female plug element of the plug connection and that the PTC heating element (40) one contact plates (128 ) forms surrounding soft elastic sealing collar (48), which is in a plug-in receptacle (44) of the partition wall (54) sealingly pressed, so that the PTC heating element (40) is frictionally held on the partition wall (54).
4. 4. PTC heating element for an electric heating device according to one of the preceding claims, wherein the PTC heating element (40) has a Heizelementgehäuse (134), the at least one PTC element (120) and the PTC element (120) energizing reeds ( 42) for the electrical connection of electrically connected to the PTC element (120) interconnects (128) adds as a structural unit, characterized in that the Heizelementgehäuse (134) is formed by an elastomer, the at least one PTC element (120 ) envelops circumferentially.
5. 5. PTC heating element according to claim 4, characterized in that the elastomeric material forming a contact tongues (42) circumferentially sealing collar (48) formed adapted as a plug connection for the holder of the PTC heating element (40).
6. 6. PTC heating element according to claim 5, characterized in that the sealing collar (48) in the direction of the free ends of the contact tongues (42) is tapered.
7. 7. PTC heating element according to one of claims 4 to 6, characterized in that the heating element housing (134) as the contact plates (128) and the at least one PTC element (120) only circumferentially captive frame (134) is formed.
8. 8. PTC heating element according to claim 7, characterized in that the frame (134) has a frame thickness which is not greater than 0.5 of the largest thickness of the sealing collar (48).
9. 9. PTC heating element one of claims 4 to 8, characterized in that opposing main side surfaces of the PTC element (120) are not covered with the elastomeric material.
10. 10. PTC heating element according to one of claims 4 to 9, characterized in that opposing main side surfaces (122) of the at least one PTC element (120) are predominantly not occupied with a contact plate.
11. 11. PTC heating element according to one of claims 4 to 10, characterized by an insulating layer (124) which is applied directly to a main side surface (122) of the PTC element (120) thermally conductive or is provided thereon.
12. 12. PTC heating element according to one of claims 4 to 11, characterized by the electrodes forming sheet metal strip (128), each forming a front side of the PTC element (120) contact strip (130) and the contact tongue (42) opposite the contact land (130) in the width plane of the PTC element (120) is propagated.
13. 13. PTC heating element according to claim 12, characterized in that the sheet-metal strip (128) on opposite end faces (126) of the PTC element (120) are electrically conductively adhered.
14. 14. Housing (22; 50) of an electrical heating device designed as a liquid heater with a connection chamber (56) and one of a medium to be heated flow through the circulation chamber (14), wherein the two chambers (56, 14) of a by the housing (22; 50) formed partition wall (54) are separated from plastic, the at least one passage opening (46) for contact tongues (42) of an in the circulation chamber (14) to be arranged PTC heating element (40) to connect in the connection chamber (56) electrically to an energization of the PTC element (120) causing line paths, characterized in that the partition (54) is a female plug element ( 44) of the PTC heating element (120) in the insertion direction frictionally and / or positively retaining plug connection is formed.

The electric heater is preferably an electric heater for a motor vehicle. In particular, it is an electric heating device for heating a liquid medium, which requires that the separating wall separating the connection chamber from the circulation chamber is made fluid-tight. Regularly leading to the circulation chamber inlet and outlet openings in the form of connecting pieces are formed, which protrude from a housing of the electric heater, which usually receives the partition in itself, outside.

The electric heater according to the present invention has a PTC heating element. Between the circulation chamber and the connection chamber, in which the contact tongues of the PTC heating element for the electrical connection are exposed, a partition wall is provided. The partition is usually part of the housing of the electric heater. The partition is usually provided inside the housing. The circulation chamber and the connection chamber are preferably each covered by housing cover, which are connected to a first and / or second housing part. Preferably, the electrical housing of the present invention is formed by a one-piece housing base part, which end is preferably closed by substantially plate-shaped cover elements. The housing base part is preferably made of plastic, preferably of a crosslinking plastic, such as a thermoset.

According to the invention, it is proposed that a plug connection is formed between the partition wall and the PTC heating element. By means of this plug-in connection, the PTC heating element is frictionally and / or positively held on the partition in a plug connection. This embodiment offers the possibility of first producing the PTC heating elements as separate components, preferably with a male plug element as part of the heating element housing. Prepared in such a way, the PTC heating elements can be at least provisionally mounted and connected by the plug connection on the partition wall alone. They are thus frictionally and / or positively held on the partition. The pre-assembled unit can be further processed. For example, a housing cover closing the circulation chamber may be applied against a housing part, for example the housing base part, to close the circulation chamber. In this case, the corresponding housing cover or a joined housing part can also be applied against the ends of the PTC heating elements to permanently secure the initially provisional connector for the operation of the PTC heater in a motor vehicle in which regularly relatively high vibrations can occur.

Although also reveals the EP 2 607 121 A1 a plug connection between a heating element housing and a partition in an air heater. However, this connection causes only a seal in the circumferential direction of the nozzle formed on the heating element housing. The connector is not suitable to hold the PTC heating element in the insertion direction frictionally and / or positively on the partition. The plug connection after EP 2 607 121 A1 holds the PTC heating element only in position relative to the partition in a direction transverse to the direction of insertion.

The plug connection associated sealing means are preferably formed so that the PTC heating element is sealed fluid-tight with respect to the partition. In this case, fluid is understood in particular to be a fluid which is introduced into the circulation chamber with overpressure. The system pressure of the liquid is about 1.5 to 3 bar. The sealants are of such quality that even at higher system pressures no liquid can pass from the circulation chamber into the connection chamber.

The heating element preferably forms the male plug element and the partition wall, the female plug element of the connector. For this purpose, the PTC heating element preferably has a soft-elastic sealing collar surrounding the contact tongues. This is pressed sealingly in a socket of the partition. The sealing collar is preferably formed integrally with the heating element housing, which is preferably formed from an elastomer for this purpose. The sealing collar is designed so that the PTC heating element is frictionally held in the insertion direction on the partition wall.

The specific embodiment of the PTC heating element according to the invention is defined in the independent claim 4 and in the related back and directed to the PTC heating element claims.

The PTC heating element according to the invention has a heating element housing formed by an elastomer. The elastomer is preferably not a thermoplastic elastomer, but a crosslinked elastomer, which is not meltable by supplying heat. This Heizelementgehäuse seals the at least one PTC element circumferentially and encloses this. By the heating element housing, a male plug element of a plug connection is preferably formed.

The elastomer preferably forms a sealing collar which circumferentially seals off the contact tongues. This sealing collar is formed adapted as a plug connection for the holder of the PTC heating element in the direction of stretching.

According to a preferred embodiment of the present invention, the sealing collar is tapered in the direction of the free ends of the contact tongues. The sealing collar can be provided as a labyrinth seal with a plurality of segments each tapering in each case. The individual segments are provided one behind the other in the longitudinal direction of the contact tongue and dimensioned, for example, so that all segments have identical maximum width. At the end of this sealing collar may be formed by the elastomeric material of the Heizelementgehäuses a stop which cooperates axially and / or radially with a counter-surface formed by the partition wall. The stop is usually shaped disc-shaped.

The sealing collar can be formed entirely from the elastomeric material. In this case, the sealing collar is penetrated only by the contact tongue forming sheet material. However, the sealing collar can also be provided as a relatively thin layer on a plug element, which is penetrated by the sheet forming the contact tongue. This plug element may for example be formed from a plastic, which is connected by means of encapsulation of the sheet material with this. A plug element can hold two contact plates at a predetermined distance and thus add. The thus prepared plug element can be used together with the contact plates, which are preferably electrically conductively contacted with the PTC element in an injection mold to form the Heizelementgehäuse by way of injection molding and with the PTC element, preferably together with an outside immediately To connect to the PTC element applied insulating layer.

Thus, it is proposed with a preferred embodiment of the present invention to form the housing as the contact plates and the at least one PTC element only circumferentially comprehensive frame. The frame forms opposing frame openings behind which the PTC element is exposed. In at least one of the frame openings is preferably the insulating plate, which is preferably formed by a ceramic plate, free. Behind the insulating usually located directly the PTC element. Thus, the contacting of the PTC element is preferably the front side, which favors a good decoupling of the heat generated by the PTC element.

The frame is formed as a relatively thin component, so that it takes up little space within the circulation chamber. This offers the possibility of arranging the individual PTC heating elements relatively close to each other within the circulation chamber. But the sealing collar extends beyond the thickness of the frame not insignificant. Thus, it is proposed according to a preferred embodiment of the present invention to form the frame with a density of not greater than 0.5 of the thickness of the sealing collar.

Furthermore, opposing main side surfaces of the PTC element are preferably predominantly not covered by the elastomer forming the heating element housing. This means that at least 85% of a major side surface of the PTC element is exposed within the frame opening and is not covered by the elastomeric material. In a corresponding manner, it is proposed that opposing main side surfaces of the PTC element are predominantly not covered with a contact plate. The contacting of the PTC elements or the PTC elements is thus predominantly, preferably exclusively, on the front side of the PTC elements or. Thus, the insulating layer is regularly applied directly to the PTC element. Particularly preferably, the PTC element is surmounted by the opposite insulating layers. The contact plate is usually that element of the PTC heating element, which forms the contact tongue and directly electrically conductively connected as an electrode to the PTC element, preferably adhered thereto.

The insulating layers may be formed from a single- or multi-layer insulating plate which covers substantially the entire main side surface of the PTC element, this regularly covered, ie at least one side, preferably multi-sided and particularly preferably fully extends beyond the PTC element. The insulating layer can be formed for example by a combination of a ceramic plate with a plastic plate. However, the insulating layer may also be formed, for example, by coating the PCT element with an electrically insulating material. In this case, the PTC element forms the substrate, and the outer surface of the insulating layer is usually inside of the plastic frame, so that a good heat dissipation results from the heat generated by the PCT element. As a coating, for example, a ceramic coating in question, which is applied by means of PVD or CVD on the PTC element as Subtrat. An insulating layer applied as an insulating coating on the main side surface of the PTC element can be combined with an insulating plate of ceramic and / or plastic.

Designed in such a way, the contact plate forms a metal strip. The sheet-metal strip preferably has a contact web which bears against the front side of the PTC element and further forms the contact tongue. The contact tongues of the two electrically conductive on opposite end faces of the PTC element adjacent sheet metal strips are each widened relative to the associated contact land in the broad plane of the PTC element. Usually, the contact tongues protrude beyond the PTC element in the length and width direction and are directed towards each other.

According to a preferred embodiment of the present invention, the plastic frame is provided on its outer side with a tapered contact web. This contact web is tapered in the thickness direction of the plastic frame. The contact bar is usually provided at least on a frame rail of the plastic frame. Particularly preferably, the contact web is provided on three successive outer sides or frame members of the plastic frame. At the contact surfaces opposite side of the plastic frame of the lower side of the support web forms a seal against the bottom of a heater housing. At right angles to the edge-side abutment webs serve to seal against a side wall of the heater housing. Thus, the PTC elements may be provided alternately offset, so that each first PTC heating element at one, for example, left side abuts against the heater housing, whereas each second PTC heating element is applied to the opposite, right housing wall. This is formed in a simple manner meandering flow channel. The edges of the system contact the PTC heating element with respect to the heater housing. The contact web is preferably formed in one piece, i. integral part of the injection-molded plastic frame. In particular, the lower contact web can also be used as a compression element to secure after installation of the PTC heating element according to the invention in the heater housing a certain mounting position by elastic biasing force. This fuse can be a mechanical fuse to mechanically fix the PTC heater to the heater housing. The biasing force can also or additionally provide for a reliable contacting of the contact tongues by biasing the PTC heating element.

According to its independent aspect, the present invention proposes a housing of an electric heater designed as a liquid heater. The housing may be formed as a housing part of the liquid heater. The housing forms at least the partition wall between the circulation chamber and the connection chamber, which has at least one passage opening for contact tongues of a PTC heating element arranged in the circulation chamber. According to the present invention, the partition with at least one female plug element of the PTC heating element in the insertion direction frictionally and / or positively retaining plug connection is formed. For this purpose, the partition may have latching means which engage with the inserted PTC heating element to hold it to the partition wall. The PTC heating element can also interact frictionally alone with the female plug element. The housing is preferably formed from a thermoset.

The present invention further relates to an electrical heating device having a housing which forms inlet and outlet openings for the fluid to be heated and a circulation chamber and a connection chamber separated from the circulation chamber by a preferably fluid-tight partition wall. In the circulation chamber, a heat-emitting surface of a PTC heating element is exposed. This heat-emitting surface is thermally coupled to a PTC element. The PTC element is contacted with electrical conductors to different polarities electrically conductive, which are electrically connected in the connection chamber.

Such an electric heater can according to EP 1 768 459 A1 be formed and used as an electric heater for air heating. But it can be designed in particular as a liquid heater, as for example from the EP 1 872 986 A1 is known. In this prior art, heating ribs protrude into the circulation chamber, through which the liquid fluid to be heated flows. The heating ribs form a U-shaped pocket, in which the PTC element and the conductor tracks and in each case on the outside of the conductor tracks insulating layers are added. As a result, the PTC elements and the current paths applied thereto on both sides are electrically insulated in the heating rib. The heating rib and the dividing wall are made of metal. By the heating rib forming walls, the heat generated by the PTC element is conducted to the outside to the outer surface of the heating fin and there delivered to the liquid medium to be heated.

The present invention relates in particular to an electrical heating device for heating a motor vehicle, in particular a passenger car. The electric heater is accordingly a component which must be economical to manufacture.

In principle, it must be ensured in the case of built-in parts for motor vehicles that the built-in parts are designed to be weight-optimized. In view of this, the also looks as generically EP 2 797 381 A1 an electric heating device with a housing which comprises a housing cover forming the partition, which is produced as an aluminum die-cast component and is sealingly placed on a housing lower part, which surrounds the circulation chamber circumferentially and which is formed as an injection-molded plastic part and thus reduced in weight.

The solution discussed last can indeed be produced more economically and is also reduced in weight compared with earlier proposals with a pure metal housing. However, especially with regard to electromobility and the increasing use of electric heaters as liquid heaters in motor vehicles, there still remains some desires.

The present invention seeks to provide an electric heater that is lightweight and inexpensive to manufacture.

1. 1. Elektrische Heizvorrichtung mit einem Gehäuse (2), das Ein- und Auslassöffnungen (10; 12) für ein zu erwärmendes Fluid und eine mit den Ein- und Auslassöffnungen (10; 12) kommunizierende Zirkulationskammer (14) ausbildet, in die zumindest ein PTC-Heizelement (40) mit zumindest einem PTC-Element (8) hineinragt, das mit Kontaktzungen (42) für den elektrischen Anschluss versehen ist, die in einer Anschlusskammer (56) freiliegen, die von der Zirkulationskammer (14) durch eine Trennwand (54) getrennt ist, wobei das Gehäuse (2) ferner eine Steuerkammer (62) zur Aufnahme einer Steuervorrichtung (106) ausbildet, die steuerungsmäßig mit dem zumindest einen PTC-Heizelement (40) gekoppelt ist, gekennzeichnet durch ein aus Kunststoff gebildetes, einteiliges Gehäusebasisteil (50), das die Trennwand (54) und Wandungen (52, 58) ausformt, die die Zirkulationskammer (14) und die Anschlusskammer (56) umfänglich umgeben.
2. 2. Elektrische Heizvorrichtung nach Anspruch 1, dadurch gekennzeichnet, dass das Gehäusebasisteil (50) die Steuerkammer (62) umfänglich umgebende Wandungen (60) ausbildet.
3. 3. Elektrische Heizvorrichtung nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass das Gehäusebasisteil (50) zwischen der Zirkulationskammer (14) und der Steuerkammer (62) eine Wandung (64) ausbildet, die mit einer Durchgangsöffnung (84) versehen ist, in die ein Kühlkörper (86) dichtend eingesetzt ist, der wärmeleitend mit der Zirkulationskammer (14) gekoppelt ist.
4. 4. Elektrische Heizvorrichtung nach Anspruch 3, dadurch gekennzeichnet, dass der Kühlkörper (86) in einem Kühlkanal (26) der Zirkulationskammer (14) freilegt, der von einer durch das Gehäusebasisteil (50) gebildeten Kanalwand (28, 30) begrenzt ist, die als Strahlungsabschirmung zwischen dem Kühlkörper (86) und dem in der Zirkulationskammer (14) vorgesehenen PTC-Heizelement (40) vorgesehen ist.
5. 5. Elektrische Heizvorrichtung nach einem der Ansprüche 3 oder 4, dadurch gekennzeichnet, dass der Kühlkörper (86) über einen Bajonettverschluss (94, 96) in der Durchgangsöffnung (84) gehalten ist.
6. 6. Elektrische Heizvorrichtung nach einem der vorherigen Ansprüche, dadurch gekennzeichnet, dass das Gehäusebasisteil (50) eine die Umfangsflächen der Zirkulationskammer bildende erste Kunststoffwanne (102), eine die Umfangsflächen der Anschlusskammer bildende zweite Kunststoffwanne (100) und eine die Umfangsflächen der Steuerkammer (62) bildende dritte Kunststoffwanne (98) ausformt, wobei die erste und die zweite Kunststoffwanne (102; 100) zu gegenüberliegenden Seiten hin offen und durch die Trennwand (54) voneinander getrennt sind und die dritte Kunststoffwanne (98) sich rechtwinklig zu der ersten und der zweiten Kunststoffwanne (102; 100) erstreckt.
7. 7. Elektrische Heizvorrichtung nach einem der vorherigen Ansprüche, dadurch gekennzeichnet, dass die die Anschlusskammer (56), die Zirkulationskammer (14) und/oder die Steuerkammer (62) umfänglich umgebenden Wandungen (58, 52, 60) stirnseitig mit einer umlaufenden Nut (68; 66; 70) versehen sind.
8. 8. Elektrische Heizvorrichtung nach einem der vorherigen Ansprüche, gekennzeichnet durch eine sich zwischen unterschiedlichen Kammern (56, 62) erstreckende, durch Umspritzen abgedichtet in dem aus einem Duroplasten geformten Gehäusebasisteil (50) aufgenommene Stromschiene (104).
9. 9. Elektrische Heizvorrichtung nach einem der vorherigen Ansprüche, dadurch gekennzeichnet, dass ein die Steuerkammer (62) unterseitig begrenzender Steuerkammerboden (64) eine die Anschlusskammer (56) umfänglich umgebende Wandung (68) ausbildet und von zumindest einer Stromschiene (104) durchsetzt ist, die in der Anschlusskammer (56) einen elektrischen Anschluss (108) zu einer in der Steuerkammer (62) aufgenommenen Leiterplatte (106) ausbildet.
10. 10. Elektrische Heizvorrichtung nach Anspruch 9, dadurch gekennzeichnet, dass die Stromschiene (104) in der Anschlusskammer (56) eine sich parallel zu den Kontaktzungen (42) des PTC-Heizelementes (40) erstreckende Anschlusszunge (108) ausbildet.
11. 11. Elektrische Heizvorrichtung nach einem der Ansprüche 3 oder 4 und 6 bis 10, soweit nicht von Anspruch 5 abhängig, dadurch gekennzeichnet, dass der Kühlkörper (86) mittels Umspritzen in dem Gehäuse (2) dichtend aufgenommen ist.

To solve this problem, the following is suggested:

1. An electric heating device having a housing (2) which forms inlet and outlet openings (10; 12) for a fluid to be heated and a circulation chamber (14) communicating with the inlet and outlet openings (10; 12) into which at least one PTC heating element (40) with at least one PTC element (8) projects, which is provided with contact tongues (42) for the electrical connection, which are exposed in a connection chamber (56) from the circulation chamber (14) by a partition ( 54), the housing (2) further forming a control chamber (62) for receiving a control device (106) which is controllably coupled to the at least one PTC heating element (40), characterized by a one-piece housing base formed of plastic (50) forming the partition wall (54) and walls (52, 58) circumferentially surrounding the circulation chamber (14) and the connection chamber (56).
2. 2. Electric heating device according to claim 1, characterized in that the housing base part (50) forms the control chamber (62) circumferentially surrounding walls (60).
3. 3. Electrical heating device according to claim 1 or 2, characterized in that the housing base part (50) between the circulation chamber (14) and the control chamber (62) forms a wall (64) which is provided with a passage opening (84) in the a heat sink (86) is sealingly inserted, which is thermally conductively coupled to the circulation chamber (14).
4. 4. An electric heater according to claim 3, characterized in that the heat sink (86) in a cooling channel (26) of the circulation chamber (14) exposed, which is bounded by a by the housing base part (50) formed channel wall (28, 30) is provided as a radiation shield between the heat sink (86) and provided in the circulation chamber (14) PTC heating element (40).
5. 5. Electric heating device according to one of claims 3 or 4, characterized in that the cooling body (86) via a bayonet closure (94, 96) is held in the passage opening (84).
6. 6. Electrical heating device according to one of the preceding claims, characterized in that the housing base part (50) forming a peripheral surfaces of the circulation chamber first plastic tub (102), a peripheral surfaces of the connection chamber forming the second plastic tub (100) and the peripheral surfaces of the control chamber (62 forming the third plastic trough (98), wherein the first and second plastic troughs (102, 100) are open to opposite sides and separated by the dividing wall (54) and the third plastic trough (98) is perpendicular to the first and second plastic troughs (98) second plastic tub (102, 100) extends.
7. 7. Electrical heating device according to one of the preceding claims, characterized in that the connecting chamber (56), the circulation chamber (14) and / or the control chamber (62) circumferentially surrounding walls (58, 52, 60) frontally with a circumferential groove ( 68, 66, 70).
8. 8. Electric heating device according to one of the preceding claims, characterized by a between different chambers (56, 62) extending, sealed by encapsulation in the formed of a thermoset housing base part (50) received busbar (104).
9. 9. Electric heating device according to one of the preceding claims, characterized in that a control chamber (62) underside delimiting control chamber bottom (64) forms a connection chamber (56) circumferentially surrounding wall (68) and is penetrated by at least one bus bar (104) in the connection chamber (56) has an electrical connection (108) to one in the control chamber (62 ) formed circuit board (106) forms.
10. 10. Electric heating device according to claim 9, characterized in that the bus bar (104) in the connection chamber (56) forms a parallel to the contact tongues (42) of the PTC heating element (40) extending terminal tongue (108).
11. 11. Electric heating device according to one of claims 3 or 4 and 6 to 10, as far as not dependent on claim 5, characterized in that the heat sink (86) by means of encapsulation in the housing (2) is sealingly received.

The electric heating device has a housing which forms the circulation chamber and the connection chamber, wherein the fluid to be heated flows in the circulation chamber and in the connection chamber the electrical connection of the PTC heating element to the power flow takes place. It goes without saying that several PTC heating elements can be provided in the circulation chamber. These can be grouped in a manner known per se within the connection chamber via an electrically conductive plate or circuit board to heating circuits. This electrical conductive plate or board can be characterized by the absence of any electronic components and serves only to group the individual PTC elements to heating circuits. Such a plate is preferred according to the teaching of EP 2 505 931 educated. In parallel to this, in the connection chamber, a further electrically conductive plate or circuit board may be provided, which may be equipped with components in order to process or control the control current and / or the power current to the individual PTC heating elements.

The present invention is characterized by a housing base formed of plastic, which forms the partition wall and walls surrounding the circulation chamber and the connection chamber circumferentially. This housing base part is formed as a one-piece component. It forms the base of the housing, which is made of plastic, preferably made entirely of plastic. The housing base part basically defines the circulation chamber and the connection chamber. Only end covers must be placed on the housing base part, on the one hand completely complete the circulation chamber and on the other hand, the connection chamber. The housing base part further forms the inlet and outlet openings to the circulation chamber, particularly preferably in the form of connecting pieces for the connection of a liquid hose or tube.

In a cross-sectional view, the housing base part is H-shaped, wherein the transverse web of the H is formed by the partition wall, which defines the connection chamber on one side and the circulation chamber on the other side. From the housing base part may further be formed a substantially perpendicular projecting from the partition wall division which divides the circulation chamber into an inlet circulation chamber and an outlet circulation chamber. As a result of the division, two heating chambers are formed within the circulation chamber, in each of which at least one PTC element is located, one of the heating chambers communicating directly with the inlet opening and the other of the heating chambers with the outlet opening. In between a connection channel is usually provided. This may be formed by a channel wall extending at right angles to the partition wall and at right angles to the partition, which is also formed as part of the housing base. The division and the channel wall may be continued by corresponding wall segments, which may be formed by a cover covering the circulation chamber. However, such a housing cover is usually located with its outer peripheral surface directly on the surrounding the circulation chamber and formed by the housing base walls.

The present invention thus offers the possibility of forming the central element of the heating device as a one-piece component through the housing base part. The housing base part can form therein plug-in receptacles for the sealing arrangement of PTC heating elements within the partition, which are first attached by plugging on the partition wall.

The heating device according to the invention also has a control chamber for receiving a control device, which is formed in a structural unit with the power section of the electric heater. The power section is formed in particular by the circulation chamber and the PTC heating elements accommodated therein. This control chamber may be formed together with the connection chamber. In this case, the electric heater has only two chambers. Alternatively, the control chamber may also be designed as a separate chamber to the connection chamber. In this case, the connection chamber, for example, only receives electrically conductive plates or boards, which serve the grouping of individual PTC heating elements to a heating circuit. A printed circuit board equipped with electronic components takes the Connection chamber then not on. Such a printed circuit board is provided in the control chamber provided separately for this purpose. This control chamber is formed by the housing. According to a preferred embodiment of the present invention, the housing base also forms the walls surrounding the control chamber circumferentially. In this preferred development are thus at least three different chambers, each of which has a specific function, namely on the one hand the heating of the preferably liquid fluid to be heated (circulation chamber), the grouping of the PTC heating elements to heating circuits (terminal chamber) and finally the processing or control of control signals and power flow (control chamber).

The housing base part is preferably formed of a crosslinking plastic, so no thermoplastic, but for example, a thermoset. The selection of this material leads to a special technical effect, provided that between two different chambers of the electric heater, a bus bar is provided extending, which is received by means of encapsulation in the housing base part. In this case, the busbar is sealed by the encapsulation received in the housing base part, d. H. in a wall that separates a connection chamber from the other connection chamber. The busbar preferably forms at opposite ends contact tongues for the attachment of a conductive plate or board. As a result, electrical conductor tracks, for example, a printed circuit board or an electrically conductive plate can be plugged by placing in a simple manner with the busbar. It has been found that thermosets cause an intimate and sealing bond with the busbar during encapsulation.

The corresponding wall may be formed by the partition wall between the circulation chamber and the connection chamber. However, it can also be formed by a wall which extends between the connection chamber and the control chamber.

Such a wall is preferably formed as a control chamber bottom through the housing base. Such a control chamber bottom preferably has a passage opening in which a heat sink is sealingly inserted. The heat sink is coupled with its one end heat-conducting with the circulation chamber and with its other end within the control chamber with a power dissipation-generating component of the control device. The heat sink may be formed entirely of metal, such as aluminum or copper. In the case where the control chamber is identical to the connection chamber, the control chamber floor mentioned here corresponds to the partition wall provided between the circulation chamber and the connection chamber, which in this case is provided with the passage opening.

According to a preferred embodiment of the present invention, the heat sink is exposed in a cooling channel of the circulation chamber. This cooling channel be the previously mentioned connection channel within the circulation chamber, which is divided by a channel wall of the heating chamber. Placing the end of the heat sink to be cooled behind the duct wall results in radiation shielding between the heat sink and the PTC heating element provided in the circulation chamber. Thus, the heat sink is not applied directly to the radiant heat emitted by the PTC heating element. This formulation is intended to express that the end of the heat sink to be cooled is indeed exposed in the circulation chamber, but does not "see" any PTC element.

The heat sink is preferably held in the passage opening via a bayonet closure. In this case, the heat sink may be formed as a substantially cylindrical member, which is surmounted on opposite circumferential segments of locking projections, which abut after joining the bayonet closure usually on one of the circulation chamber circumferentially surrounding walls, whereby the cooling element is locked. It goes without saying that the passage opening must be provided with axially extending grooves, which are designed to carry out the locking projections suitable, as is usual in a bayonet fitting. For joining the heat sink, this is usually inserted from the control chamber side in the direction of the circulation chamber, usually with entrainment and inclusion of a sealing element, for example in the form of a sealing ring, which seals the heat sink against the wall defining the passage opening. On its side facing away from the circulation chamber, the heat sink usually has a collar which abuts against an edge bordering the passage opening on the control side.

In the previously discussed further development with a circulation chamber, a connection chamber and a control chamber, wherein connection chamber and control chamber are provided separately from each other, the housing base part preferably forms a first plastic tub, which forms the peripheral surfaces of the circulation chamber, a second plastic tub, which forms the peripheral surfaces of the connection chamber , and a third plastic tub, which forms the peripheral surfaces of the control chamber. As already mentioned, usually the first and the second plastic tub divide a floor formed by the partition wall. Thus, the first and the second plastic tub are open to opposite sides and separated from each other by the partition wall. The third plastic tub extends at right angles to the first and the second plastic tub. Accordingly, the main extension direction of the third plastic tub covering the housing cover is perpendicular to the main extension direction of the housing cover, which cover the first and the second plastic tub. The bottom of the third plastic tub is usually formed by a wall segment formed by the housing base part, which usually forms a circumferential wall of the connection chamber and a peripheral wall of the circulation chamber in a straight line extension.

Each of the aforementioned housing cover to the connection chamber, the circulation chamber and the control chamber is preferably made of plastic, particularly preferably made of thermosetting plastic. For tight connection between the respective housing cover and the housing base part, the walls surrounding the connection chamber, the circulation chamber and / or the control chamber are provided with a circumferential groove on the front side. In this groove, an adhesive, in particular an epoxy adhesive is introduced before joining the respective housing cover. The housing cover has a circumferential rim, which is introduced into the circumferential groove and forms a counter groove together with another parallel circumferential web, in which usually an inner web which limits the circumferential groove inwardly engages, after which a kind of labyrinth seal is formed due to the volumetric dosing of the adhesive in the groove after pressing the housing cover is substantially completely filled by adhesive.

According to a preferred development of the present invention, a bus bar extending between two different chambers is provided, which is received in the housing base part in a sealed manner by means of encapsulation. This is formed in particular for this preferred embodiment of a thermoset. The thermoset surrounds and seals the busbar within the material so that a secure seal is provided between the two chambers along the busbar outer surface.

Such a configuration may for example be provided passing through a control floor between the control chamber and the connection chamber. Such a control chamber bottom bounded below the control chamber and forms a peripheral wall surrounding the connection chamber. The power rail provided in this manner is formed in the development of the present invention as a connection element between a recorded in the control chamber circuit board and the connection chamber. The busbar may be provided as a plug-in element and be electrically contacted by plug contacts with the circuit board on the one hand and a conductive plate provided within the connection chamber on the other hand. This plate can according to EP 2 505 931 A1 be educated. Within the terminal chamber formed by the busbar plug contact preferably extends parallel to the contact tongues of the PTC heating element, so that the plug contact to the PTC heating element and the plug contact to the busbar by attaching an electrically conductive plate in a predetermined direction, usually by sinking the conductive plate can be effected in the connection chamber.

According to a preferred development of the present invention, the heat sink is sealingly received in the housing by insert molding. Also in this embodiment, the housing is preferably formed from a thermoset. The heat sink may have on its outer peripheral surface one or more regularly circumferentially encircling mounting collar, which form a labyrinth seal together with the solidified plastic of the housing and accordingly improve both the secure attachment of the heat sink in the housing as well as the tightness. During encapsulation, a surface of the heat sink facing the connection chamber can be coated by a plastic which completely or partially forms the housing in order to create an electrically insulating contact surface for a power transistor, which is thermally conductively connected to the heat sink, by the power loss generated by the power transistor to deliver the medium to be heated within the circulation chamber. The insulation may be integrally formed with the housing as a thin film. As a result, it is possible to dispose of a separate electrical insulation between the heat sink and the power transistor. The production is simplified.

The present invention further relates to an electric heating device with the preamble features of claim 1.

Such an electric heater is made of from the EP 2 607 121 A1 known.

The present invention seeks to provide an electric heater that allows high heat density and good efficiency.

1. 1. Elektrische Heizvorrichtung mit einem Gehäuse (2), das Ein- und Auslassöffnungen (10, 12) für das zu erwärmende Fluid und eine Zirkulationskammer (14) ausbildet, in der eine wärmeabgebende Fläche eines PTC-Heizelementes (40) freiliegt, die wärmeleitend mit einem PTC-Element (120) gekoppelt ist, das mit elektrischen Leiterbahnen (128) zu unterschiedlichen Polaritäten elektrisch leitend kontaktiert ist, dadurch gekennzeichnet, dass die Leiterbahnen (128) an Stirnseitenflächen (126) des PTC-Elementes (120) elektrisch leitend kontaktiert sind.
2. 2. PTC-Heizelement (40) mit einem PTC-Element (120), das mit elektrischen Leiterbahnen (128) zu unterschiedlichen Polaritäten elektrisch leitend kontaktiert ist, dadurch gekennzeichnet, dass die Leiterbahnen jeweils durch Blechstreifen (128) gebildet sind, die jeweils einen stirnseitig an dem PTC-Element (120) anliegenden Kontaktsteg (130) und eine Kontaktzunge (42) ausbildet.
3. 3. PTC-Heizelement (40) nach Anspruch 2, dadurch gekennzeichnet, dass die beiden Kontaktzungen (42) der Leiterbahnen das PTC-Element (120) an einer Stirnseite in Längserstreckungsrichtung des zugehörigen Kontaktsteges (130) überragen und quer zur Längserstreckungsrichtung des zugehörigen Kontaktstege (130) das PTC-Element (120)teilweise überragend aufeinander zugerichtet sind.
4. 4. PTC-Heizelement (40) nach Anspruch 2 oder 3, dadurch gekennzeichnet, dass die Kontaktstege (130) eine geringere Dicke als das PTC Element haben.
5. 5. PTC-Heizelement (40) nach einem der vorherigen Ansprüche 2 bis 4, dadurch gekennzeichnet, dass die Blechstreifen (128) mit dem PTC-Element (120) verklebt sind.
6. 6. PTC-Heizelement (40) nach einem der vorherigen Ansprüche 2 bis 5, dadurch gekennzeichnet, dass die Blechstreifen (128) eine sich gegenüberliegend zu der mit dem PTC-Element (120) kontaktierten Kontaktfläche liegende Randfläche (132) ausbilden, die auf ganzer Länge des Blechstreifens (128) eben ist.
7. 7. PTC-Heizelement (40) nach einem der vorherigen Ansprüche 2 bis 6, gekennzeichnet durch, eine Isolierlage (124), die unmittelbar an einer Hauptseitenfläche (122) des PTC-Elementes (120) wärmeleitend anliegt und eine Wärme abgebende Außenfläche des PTC-Heizelementes (40) ausbildet.
8. 8. PTC-Heizelement (40) nach einem der vorherigen Ansprüche 2 bis 7, dadurch gekennzeichnet, dass das PTC-Element (120) vollumfänglich unter Einschluss von sämtlichen Randflächen der Isolierlage (124) in einem Kunststoffrahmen (134) eingebettet ist.
9. 9. PTC-Heizelement (40) nach Anspruch 8, dadurch gekennzeichnet, dass der Kunststoffrahmen (134) durch Umspritzen mit den PTC-Element (120) und der Isolierlage (124) verbunden ist.

To solve this problem, the following is suggested:

1. An electric heater comprising a housing (2) forming inlet and outlet openings (10, 12) for the fluid to be heated and a circulation chamber (14) exposing a heat-emitting surface of a PTC heating element (40) which conducts heat is coupled to a PTC element (120) which is electrically conductively contacted with electrical conductor tracks (128) to different polarities, characterized in that the conductor tracks (128) on the end faces (126) of the PTC element (120) electrically conductively contacted are.
2. 2. PTC heating element (40) having a PTC element (120) which is electrically conductively contacted with electrical conductor tracks (128) to different polarities, characterized in that the conductor tracks are each formed by metal strips (128), each having a end face on the PTC element (120) adjacent contact web (130) and a contact tongue (42) is formed.
3. 3. PTC heating element (40) according to claim 2, characterized in that the two contact tongues (42) of the conductor tracks project beyond the PTC element (120) on an end side in the longitudinal extension direction of the associated contact web (130) and transversely to the longitudinal direction of the associated contact webs (130) the PTC element (120) are partially aligned facing each other.
4. 4. PTC heating element (40) according to claim 2 or 3, characterized in that the contact webs (130) have a smaller thickness than the PTC element.
5. 5. PTC heating element (40) according to one of the preceding claims 2 to 4, characterized in that the metal strips (128) are glued to the PTC element (120).
6. 6. PTC heating element (40) according to one of the preceding claims 2 to 5, characterized in that the sheet metal strips (128) form a lying opposite to the contacted with the PTC element (120) contact surface edge surface (132) lying on the entire length of the metal strip (128) is flat.
7. 7. PTC heating element (40) according to one of the preceding claims 2 to 6, characterized by, an insulating layer (124), which bears directly on a main side surface (122) of the PTC element (120) thermally conductive and a heat-emitting outer surface of the PTC Heating element (40) is formed.
8. 8. PTC heating element (40) according to one of the preceding claims 2 to 7, characterized in that the PTC element (120) is fully embedded, including all edge surfaces of the insulating layer (124) in a plastic frame (134).
9. 9. PTC heating element (40) according to claim 8, characterized in that the plastic frame (134) is connected by encapsulation with the PTC element (120) and the insulating layer (124).

The electric heater has a housing with inlet and outlet openings for the fluid to be heated. The fluid to be heated may be a gaseous fluid. It can also be a liquid fluid. The fluid is passed through a circulation chamber in which the heat-emitting surfaces of a PTC heating element are exposed. These surfaces are thermally coupled with a PTC element. This PTC element is contacted with electrical conductors to different polarities electrically conductive. The electrical heating device differs from previously known heating devices in that the conductor tracks are contacted in an electrically conductive manner on end faces of the PTC element. In this case, end surfaces are those surfaces which extend at right angles to the main side surfaces of the PTC element. The PTC element usually has a plate-like configuration with a main side surface whose main directions of extension are substantially larger than the extension direction of the end faces. The length or width of the PTC element is by a factor of five, preferably by a factor of ten, greater than the thickness of the end face of the PTC element. Such an embodiment has proven itself in any case in electric heaters for motor vehicles, which takes the present invention particularly into view. The heat of the PTC element is decoupled via the main side surfaces. Usually, a contact plate is applied to these main side surfaces in electrical heating devices in the prior art.

According to the proposal of the present invention, the contacting takes place on a side surface of the PTC element which extends at right angles thereto. Thus, the PTC element can be exposed directly or only with the interposition of an insulating layer in the circulation chamber. In the former case, the heat-emitting surface of the PTC element is formed by the PTC element itself. In the second case, the heat-emitting outer surface is formed by the outer surface of the insulating layer. This insulating layer may be a ceramic plate.

Due to the front-side contacting of the PTC element, a plurality of PTC elements can be arranged to form a channel for the fluid to be heated relatively close together in the circulation chamber. One on both major side surfaces of the PTC element provided contact plate is missing. So the PTC heating elements are less thick. The PTC heating elements are preferably used as heating ribs directly in a circulation housing of a water heater. Thus, a high heat density can be achieved in the electric heater. Due to the lack of contact plates, which are provided parallel to the main side surfaces of the PTC element, the heat can be dissipated via these main side surfaces of the PTC element better than in the prior art. The heat is usually introduced directly into the insulating layer and there discharged by means of heat conduction on the outer surface, which is exposed in the flow of fluid to be heated.

The present invention further proposes a PTC heating element with a PTC element and electrical conductor tracks, which can be assigned to different polarities and are contacted in an electrically conductive manner with the PTC element. The conductor tracks are each formed by a metal strip. Each of the sheet-metal strips is preferably contacted in each case directly on the front side of the PTC element, i. is directly adjacent to a metallic layer of the PTC element. For this purpose, the metal strip preferably has a contact web, which preferably bears solely on the end face of the PTC element, i. does not extend beyond the major side surfaces of the PTC element. The metal strip preferably also forms a contact tongue. This contact tongue is formed as a male plug-in element of an electrical plug-in connection, so that the PTC element can be electrically contacted in an electrical heating device by plugging it into a female electrical plug element receptacle. Preferably, the contact web in the width direction of the PTC element is narrower than the contact tongue formed. Thus, the PTC heating element can be formed with a width which is only slightly larger than the width of the PTC element.

According to a preferred embodiment of the present invention, the two contact tongues of the conductor tracks project beyond the PTC element on a single end face, specifically in the longitudinal direction of extension of the associated contact web. Transverse to this extension direction are the contact tongues that the PTC element partially directed superior to each other. Thus, the contact webs in the width direction are narrower than the contact tongues formed, but this does not lead to an additional width of the PTC heating element, since the contact tongues are directed towards each other. In other words, the contact tongues project partially in the width direction of the PTC element.

At least the contact webs, regularly the two metal strips in total, preferably have a smaller thickness than the PTC element. The sheet-metal strips arranged on the end side on the PTC element and preferably glued therewith can thus be surmounted, at least at the height of the PTC element, by an insulating layer placed on the main side surface of the PTC element. Thus, this insulating layer can end approximately at the height of the contact webs and be connected there to a heating element housing of the PTC heating element forming plastic frame, preferably by molding of the plastic frame forming plastic material. This plastic material is preferably elastomeric material, but usually not a thermoplastic elastomer, but crosslinking elastomer.

The contact tongues themselves may be formed with reduced thickness relative to the thickness of the contact webs. The contacting of the contact tongues usually takes place at the lying in the plane of the main side surface of the PTC element surfaces of the contact tongue.

In view of a small width of the PTC heating element, the metal strips form an edge surface which is flat over the entire length of the metal strip. In this edge surface is that outer surface of the metal strip, which is opposite to the contact surface. The contact surface of the sheet metal strip is that surface which bears directly against the PTC element and introduces the power current into the front side of the PTC element. By the flat edge surface, a relatively narrow heating element housing can be formed, which favors a compact arrangement of the PTC elements in the electric heater and thus a high heat density.

As already mentioned, the heating element housing is preferably formed by a plastic frame surrounding the PTC element in its entirety. In this case, preferably all edge surfaces of the insulating layer are enveloped by the plastic frame. Preferably, the metal strip is also predominantly embedded in the plastic frame. Only the contact tongues protrude on one side beyond the plastic frame.

The present invention finally relates to an electrical heating device having a housing which forms inlet and outlet openings for the fluid to be heated and a circulation chamber and a connection chamber separated from the circulation chamber by a preferably fluid-tight partition wall. In the circulation chamber, a heat-emitting surface of a PTC heating element is exposed. This heat-emitting surface is thermally coupled to a PTC element. The PTC element is contacted with electrical conductors to different polarities electrically conductive, which are electrically connected in the connection chamber.

Such an electric heater can according to EP 1 768 459 A1 be formed and used as an electric heater for air heating. But it can be designed in particular as a liquid heater, as for example from the EP 1 872 986 A1 is known. In this prior art, heating ribs protrude into the circulation chamber, through which the liquid fluid to be heated flows. The heating ribs form a U-shaped pocket, in which the PTC element and the conductor tracks and in each case on the outside of the conductor tracks insulating layers are added. As a result, the PTC elements and the current paths applied thereto on both sides are electrically insulated in the heating rib. The heating rib and the dividing wall are made of metal. By the heating rib forming walls, the heat generated by the PTC element is conducted to the outside to the outer surface of the heating fin and there delivered to the liquid medium to be heated.

The present invention relates in particular to an electrical heating device for heating a motor vehicle, in particular a passenger car. The electric heater is accordingly a component which must be economical to manufacture. Furthermore, it must be ensured in principle with built-in parts for motor vehicles that the built-in parts are designed to optimize weight. In view of this, the also looks as generically EP 2 797 381 A1 an electric heating device with a housing which comprises a housing cover forming the partition, which is produced as an aluminum die-cast component and is sealingly placed on a housing lower part, which surrounds the circulation chamber circumferentially and which is formed as an injection-molded plastic part and thus reduced in weight.

The solution discussed last can indeed be produced more economically and is also reduced in weight compared with earlier proposals with a pure metal housing. However, especially with regard to electromobility and the increasing use of electric heaters as liquid heaters in motor vehicles, there still remains some desires.

The present invention seeks to provide an electric heater that is lightweight and inexpensive to manufacture.

1. 1. Elektrische Heizvorrichtung mit einem Gehäuse (2), das Ein- und Auslassöffnungen (10; 12) für das zu erwärmende Fluid und eine Zirkulationskammer (14) und eine von der Zirkulationskammer (14) durch eine Trennwand getrennte Anschlusskammer (56) ausbildet, wobei in der Zirkulationskammer (14) eine wärmeabgebende Fläche eines PTC-Heizelementes (40) freiliegt, die wärmeleitend mit einem PTC-Element gekoppelt (120) ist, das mit elektrischen Leiterbahnen (128) zu unterschiedlichen Polaritäten elektrisch leitend kontaktiert ist, die in der Anschlusskammer (56) elektrisch angeschlossen sind, dadurch gekennzeichnet, dass das Gehäuse (2) ein Kunststoffgehäuse (50, 72, 80, 82) ist, das mit einer Abschirmung (110, 112) versehen ist.
2. 2. Elektrische Heizvorrichtung nach Anspruch 1, dadurch gekennzeichnet, dass die Abschirmung durch ein in dem Kunststoffgehäuse (50, 72, 80, 82) integriertes Metallgitter gebildet ist.
3. 3. Elektrische Heizvorrichtung nach einem der vorherigen Ansprüche, dadurch gekennzeichnet, dass die Abschirmung mittels Umspritzen eines das Kunststoffgehäuse (50, 72, 80, 82) bildenden Kunststoffmaterials mit dem Kunststoffgehäuse verbunden ist.
4. 4. Elektrische Heizvorrichtung nach einem der vorherigen Ansprüche, dadurch gekennzeichnet, dass das Gehäuse (2) eine Steuervorrichtung (106) in sich aufnimmt, die von der Abschirmung (110, 112) umfänglich umgeben ist.
5. 5. Elektrische Heizvorrichtung nach einem der vorherigen Ansprüche, gekennzeichnet durch eine durch das Kunststoffgehäuse (50, 72, 80, 82) ausgebildete Steuerkammer (62), in der eine Steuervorrichtung (106) aufgenommen ist.
6. 6. Elektrische Heizvorrichtung nach einem der vorherigen Ansprüche, gekennzeichnet durch wenigstens eine, eine Wand (64) des Kunststoffgehäuses (50, 72, 80, 82) durchsetzende Stromschiene (104), die durch Umspritzen dichtend in der Wand (64) aufgenommen ist, wobei das Kunststoffgehäuse (50, 72, 80, 82) aus einem Duroplasten gebildet ist.
7. 7. Elektrische Heizvorrichtung nach einem der vorherigen Ansprüche, dadurch gekennzeichnet, dass das Metallgehäuse aus zumindest zwei Schalenelementen (110, 112) gebildet ist, die zwischen sich die Ein- und Auslassöffnungen (10; 12) ausbildende Ein- und Auslassstutzen (6; 8) des Gehäuses aufnehmen.
8. 8. Elektrische Heizvorrichtung nach einem der vorherigen Ansprüche, dadurch gekennzeichnet, dass das Metallgehäuse (110, 112) Ausnehmungen (115) aufweist, durch welche durch das Kunststoffgehäuse (50, 72, 80, 82) gebildete Befestigungsvorsprünge (114) die Außenfläche des Metallgehäuses (110, 112) überragen.
9. 9. Elektrische Heizvorrichtung nach einem der vorherigen Ansprüche, dadurch gekennzeichnet, dass das Kunststoffgehäuse (50, 72, 80, 82) aus einem Duroplast gebildet ist.

To solve this problem, the following is proposed:

1. An electric heater comprising a housing (2) forming inlet and outlet openings (10; 12) for the fluid to be heated and a circulation chamber (14) and a connection chamber (56) separated from the circulation chamber (14) by a partition wall, wherein in the circulation chamber (14) a heat-emitting surface of a PTC heating element (40) is exposed, which is heat-conductively coupled to a PTC element (120) which is electrically conductively contacted with electrical conductor tracks (128) to different polarities, in the Connection chamber (56) are electrically connected, characterized in that the housing (2) is a plastic housing (50, 72, 80, 82) which is provided with a shield (110, 112).
2. 2. Electric heating device according to claim 1, characterized in that the shield is formed by a in the plastic housing (50, 72, 80, 82) integrated metal grid.
3. 3. Electrical heating device according to one of the preceding claims, characterized in that the shield is connected by means of encapsulation of a plastic housing (50, 72, 80, 82) forming plastic material with the plastic housing.
4. 4. Electric heating device according to one of the preceding claims, characterized in that the housing (2) receives a control device (106) in itself, which is surrounded by the shield (110, 112) circumferentially.
5. 5. Electric heating device according to one of the preceding claims, characterized by a through the plastic housing (50, 72, 80, 82) formed control chamber (62) in which a control device (106) is accommodated.
6. 6. Electrical heating device according to one of the preceding claims, characterized by at least one, a wall (64) of the plastic housing (50, 72, 80, 82) passing through busbar (104) which is received by encapsulation sealing in the wall (64), wherein the plastic housing (50, 72, 80, 82) is formed of a thermosetting plastic.
7. 7. Electrical heating device according to one of the preceding claims, characterized in that the metal housing of at least two shell elements (110, 112) is formed, which between them the inlet and outlet openings (10; 12) forming the inlet and outlet nozzles (6; ) of the housing.
8. 8. Electric heating device according to one of the preceding claims, characterized in that the metal housing (110, 112) has recesses (115) through which through the plastic housing (50, 72, 80, 82) formed fastening projections (114), the outer surface of the metal housing (110, 112) protrude.
9. 9. Electric heating device according to one of the preceding claims, characterized in that the plastic housing (50, 72, 80, 82) is formed of a thermosetting plastic.

The electric heating device has a housing which forms the circulation chamber and the connection chamber, wherein the fluid to be heated flows in the circulation chamber and in the connection chamber the electrical connection of the PTC heating element to the power flow takes place. It goes without saying that several PTC heating elements can be provided in the circulation chamber. These can be grouped in a manner known per se within the connection chamber via an electrically conductive plate or circuit board to heating circuits. This electrical conductive plate or board can be characterized by the absence of any electronic components and serves only to group the individual PTC elements to heating circuits. It can in particular according to EP 2 505 931 A1 be educated. In parallel thereto, a further electrically conductive plate or circuit board can be provided in the connection chamber, which can be equipped with components in order to process or control the control current and / or the power current to the individual PTC heating elements.

The present invention differs from the prior art in that the housing is a plastic housing. Accordingly, the circulation chamber and the connection chamber and the separating wall separating the two chambers, which is preferably a fluid-tight partition, are completely surrounded by plastic walls. Thus, the walls surrounding the connection chamber at least circumferentially, the walls surrounding the circulation chamber and the plastic partition usually extending at right angles thereto are formed. This part of the housing may be formed as a unitary housing base body, i. be manufactured as a single component by way of injection molding. The circulation chamber and / or the cover chamber covering the top side can also be made of plastic, so that the total connection chamber and the circulation chamber is formed and limited in total of plastic components / are. Optionally, however, the housing cover may consist of a thin metal sheet, which contributes only slightly to increase the dead weight of the housing.

According to the present invention, the plastic housing is further provided with a shield. This shield encloses the housing substantially fully to provide effective EMC protection for the electric heater. Thus, the circuit operations performed in the electric heater cause no significant electromagnetic interference within the vehicle.

The shield is preferably provided with a ground connection. This ground connection is embodied, for example in the form of a plug-in contact element or a fastening eye. About this ground terminal, the electric heater after installation in the vehicle to the ground terminal of the vehicle can be connected. The ground terminal is usually exposed outside the housing. It may also be part of the attachment of the housing to the vehicle, so that the ground connection is realized when a fastening bolt or screw is connected to the housing of the electric heater to mount the electric heater to the vehicle.

The plastic housing may be penetrated by a ground monitor connector, for example, protrudes into the circulation chamber to check whether the electrical insulation of the PTC heating element is functional within the circulation chamber. Such a ground monitor can be exposed as a terminal bolt on the outside of the housing of the electric heater. The ground monitor may be provided, for example, in connection with a fastening eye, via which the electric heater is mounted and secured to a motor vehicle. The ground terminal is usually electrically coupled to the shielding of the housing. A ground monitor connection has no function serving the electrical supply of the PTC elements. He alone checks the electrical insulation of the PTC element relative to the housing or the fluid to be heated.

The ground monitor may be electrically connected within the housing to the aforementioned ground terminal. The conduction can be done for example via the shield of the housing.

In addition to the connection chamber can be formed by the plastic housing a control chamber in which a control device is received. This provided in structural unit with the actual heating part control device is coupled in terms of control with the PTC heating element. Usually, an electrical connection, for example in the form of a plug contact between a heating circuit forming the conductive plate and a circuit board of the control device is provided. Such an electrical connection can be formed for example by a busbar, which is received by encapsulation sealing in the wall of the plastic housing. In this case, the plastic housing is preferably made a crosslinking plastic, in particular a thermoset formed. The plastic housing is therefore preferably not formed from a thermoplastic. A crosslinking plastic offers in a special way the ability to seal the bus bar in the wall of the plastic housing. The penetrated by the busbar wall may also be formed by the partition to electrically connect, for example, one or more PTC heating elements within the circulation chamber. The corresponding development can also be essential to the invention. Such a juxtaposed object is formed, for example, by the features of the preamble of claim 1 and the characterizing features of claim 6.

According to a preferred development of the present invention, the shield is formed by a metal grid integrated in the plastic housing. In this preferred embodiment, the shield is not regularly on the outside of the housing. Rather, the shield is within the housing, i. the respective chambers provided, for example, lining or absorbed by encapsulation in the plastic housing. For attachment, the shield can be connected by means of encapsulation of the plastic housing forming plastic material with the plastic housing in a simple manner.

According to a preferred development of the present invention, the housing accommodates a control device, which is surrounded circumferentially by the shield. This part of the shield can also be formed by an integrated metal grid.

Alternatively, the shield may also be formed by a metal housing surrounding the plastic housing on the outside. This metal housing may consist of a grid material for weight reduction. Alternatively, a continuous sheet metal forming the metal housing.

This metal housing is preferably formed from at least two shell elements, which receive between the inlet and outlet opening forming inlet and outlet ports of the housing.

The metal housing may have recesses through which fastening projections project beyond the outer surface of the metal housing, wherein these fastening projections are formed by the plastic housing and the attachment of the electric heater to the vehicle, for example, to receive fastening bolts or screws in it.

• 1 eine perspektivische Draufsicht auf ein erstes Ausführungsbeispiel eines Gehäuses;
• 2 eine perspektivische Seitenansicht des in 1 gezeigten Ausführungsbeispiels;
• 3 eine in dem ersten Ausführungsbeispiel vorgesehene Abdeckplatte 22 in isolierter Darstellung zusammen mit PTC-Heizelementen;
• 4die in 3 gezeigte Abdeckplatte beim Bestücken mit einem PTC-Heizelement;
• 5 eine seitliche perspektivische Schnittansicht eines zweiten Ausführungsbeispiels der vorliegenden Erfindung;
• 6 das Detail VI gemäß der Darstellung in 5;
• 7 eine perspektivische Sicht in die Steuerwanne des zweiten Ausführungsbeispiels;
• 8 eine perspektivische Längsschnittansicht entlang der Linie VIII-VIII gemäß der Darstellung in 7;
• 9 eine perspektivische, teilweise aufgebrochene Seitenansicht des zweiten Ausführungsbeispiels mit einer an dem Kunststoffgehäuse vorgesehenen Abschirmung;
• 10 eine perspektivische Seitenansicht von Teilen des PTC-Heizelementes;
• 11 eine teilweise gebrochene perspektivische Seitenansicht des PTC-Heizelementes;
• 12 eine perspektivische Querschnittsansicht des PTC-Heizelementes;
• 13 eine Längsschnittansicht durch die Abdeckplatte gemäß den 3, 4 mit einem einzelnen darin aufgenommenen PTC-Heizelement;
• 14 eine perspektivische Seitenansicht bei entfernten Gehäusedeckel eines weitern Ausführungsbeispiels;
• 15 eine Ansicht ähnlich zu 14 ohne Gehäusedeckel des weiteren Ausführungsbeispiels und
• 16 eine perspektivische Schnittansicht druch die Trennwand des weiteren Ausführungsbeispiels.

Further details and advantages of the present invention will become apparent from the following description of an embodiment in conjunction with the drawings. In this show:

• 1 a top perspective view of a first embodiment of a housing;
• 2 a side perspective view of the 1 shown embodiment;
• 3 a cover plate 22 provided in the first embodiment in isolated form together with PTC heating elements;
• 4the in 3 shown cover plate when populated with a PTC heating element;
• 5 a side sectional perspective view of a second embodiment of the present invention;
• 6 the detail VI as shown in 5 ;
• 7 a perspective view into the control trough of the second embodiment;
• 8th a longitudinal perspective view along the line VIII-VIII as shown in FIG 7 ;
• 9 a perspective, partially broken side view of the second embodiment with a provided on the plastic housing shield;
• 10 a side perspective view of parts of the PTC heating element;
• 11 a partially broken perspective side view of the PTC heating element;
• 12 a perspective cross-sectional view of the PTC heating element;
• 13 a longitudinal sectional view through the cover plate according to the 3 . 4 with a single PTC heating element received therein;
• 14 a perspective side view of the removed housing cover of a further embodiment;
• 15 a view similar to 14 without housing cover of the further embodiment and
• 16 a sectional perspective view of the partition of the further embodiment.

Basic structure of the heater

1 shows a top perspective view of a reference numeral 2 characterized housing a trained as a water heater electric heater. The housing 2 has a housing pan element 4 made of plastic. This plastic is present a thermoset. The housing 2 forms an inlet nozzle 6 and an outlet 8th in the present case in one piece on the housing tub element 4 are formed. The pillars 6 . 8th are designed as hose connection pieces and form an inlet opening 10 or an outlet opening 12 to one with reference numerals 14 marked circulation chamber. The circulation chamber 14 is divided into two heating chambers, one of which is in the 1 and 2 only the front heating chamber in the illustration 16 can be seen. The subdivision of the circulation chamber 14 takes place by a one-piece on the housing tray element 4 trained and from the ground 18 inside projecting partition wall 20 , which by a to one with reference numerals 22 marked cover plate trained and with reference numerals 24 marked further partition wall 24 their continuation takes place. At the two neck 6 . 8th opposite side are the two heating chambers 16 connected by a connecting channel, which in the second embodiment of a housing 2 according to 5 to recognize and there with reference numerals 26 is marked. This connection channel 26 is through a channel wall segment 28 , which is integral to the cover plate 22 is formed and perpendicular to the partition wall 20 extends, and a channel wall segment 30 which is from the ground 18 the housing bath element 4 protrudes from the heating chamber 16 separated.

The cover plate 22 is made of plastic. In the present case is the cover plate 22 formed from a thermosetting plastic. Basically, the use of thermosets for the manufacture of the housing 2 or parts thereof have the advantage that a thermoset has a relatively high temperature resistance of about 150 ° C and even at temperatures of -40 ° C shows no brittleness. This results in a case of a thermoset completely or partially formed housing better temperature resistance to requirements that occur in heating and operation of vehicles in Arctic regions. The thermoset is also preferable to a thermoplastic because a thermoset has better creep resistance than a thermoplastic.

The 4 shows the cover plate 22 without the housing pan element 4 , The cover plate 22 has a circumferential edge 32 with one on the housing tub element 4 trained circumferential groove 34 interacts. This groove 34 is filled with glue, in this case epoxy glue, before the edge 32 in the groove 34 penetrates to the cover 22 To bond with the housing tub element. In the same way, the segments 24 respectively. 28 with the corresponding wall elements 20 respectively. 30 the housing bath element 4 together. After that is the circulation chamber 14 fluid-tight between the floor 18 the housing bath element 4 and the cover member 22 and circumferentially enclosed by walls enclosed by the housing pan element 4 are formed and perpendicular to its bottom 18 extend.

Before mounting the cover element 22 in the from the 3 and 4 apparent way with PTC heating elements 40 stocked. The PTC heating elements 40 are on the connection side, ie where the PTC heating elements 40 two contact tongues each 42 have, in female plug element receptacles 44 plugged in through the cover plate 22 be formed in one piece. This plug element recordings 44 are each end with a longitudinal slot 46 provided by the reeds 42 is penetrated (cf. 1 . 3 ). A longitudinal slot 46 forms an example of one in the cover plate 22 as an example of an inner wall recessed passage opening.

The 4 illustrates the insertion of the PTC heating element 40 in the female plug element receptacle 44 , The PTC heating element 40 has a sealing collar for the plugged-in plug connection 48 , which corresponds to the dimension of the plug element receptacle 44 adapted adapted and is formed by an elastomeric material, which within the plug element receptacle 44 is pressed tightly so that the slits 46 opposite the circulation chamber 14 sealed fluid-tight. In addition, by pressing the sealing collar 48 forming material, the PTC heating element 40 frictionally engaged within the plug element receptacle 44 held, and also in the insertion direction, the longitudinal extension direction of the contact tongues 42 equivalent. Attached in this way keep the PTC heating elements 40 on the cover plate 22 even if this with the plug element receptacles 44 is oriented downwards, as in 3 is pictured.

Housing base part

The 5 illustrates in a sectional view of the essence of an embodiment of a housing base part, which with reference numerals 50 is marked. The housing base part 50 forms with reference numerals 52 marked walls that the circulation chamber 16 Surrounded circumferentially, ie the heating chambers 16 and the connection channel 26 surrounded circumferentially. The provided in the previously described embodiment as a separate component cover plate 22 is present in one piece by the housing base part 50 formed and also here - as in the first embodiment - a partition 54 out, which is the circulation chamber 16 from a connection chamber 56 separates, in which in this case all contact tongues 42 all PTC heating elements 40 exposed. Also with reference numerals 58 characterized and the connection chamber circumferentially surrounding walls are through the housing base part 50 educated. Finally, in extension of the nozzle 6 . 8th and in that direction behind the circulation chamber 16 or the connection chamber 56 through the housing base part 50 walls 60 formed, which is a control chamber 62 surrounded circumferentially. One with reference number 64 characterized control chamber floor from which the walls 60 elevate, partially through one of the walls 52 and one of the walls 58 educated. In a cross-sectional view, which is parallel to the extension direction of the nozzle 6 . 8th runs, the housing base part accordingly appears as in cross-section H-shaped with a one side of the H scheduled U. The Gehäusebasisteil 50 is made of plastic and designed as a single component. The housing base part 50 is in the present case formed from a thermosetting plastic.

The walls 52 . 58 . 60 are each frontally with a circumferential groove 66 . 68 . 70 Mistake. The function of these grooves 66 . 68 . 70 is especially by 6 clarified. So there is a cover 72 to the control chamber 62 represented as a substantially flat plate with a circumferential rim 74 is trained. This wreath 74 engages in the associated groove 70 and displaces there introduced adhesive (in this case epoxy adhesive). The wreath 74 forms an outer edge of a counter-groove 76 attached to the cover element 72 formed and inside by an inner bridge 78 is limited. Thus, a kind of labyrinth seal is formed, in which displaced adhesive can penetrate, before the assembly of the cover 72 either in the groove 70 or the counter-groove 76 has been introduced. In a corresponding manner, the housing cover 80 to the circulation chamber 14 respectively. 82 to the connection chamber 56 formed on the edge side and on the housing base part 50 attached and sealed against it.

Like also 6 clarifies, is the control chamber floor 64 provided with a through hole 84 into which a heat sink 86 is introduced. For sealing the circulation chamber 14 with respect to the control chamber 62 is between the heat sink 86 and the inner peripheral wall of the through hole 84 a sealing ring 88 intended. The heat sink 86 forms control housing side an annular stop 90 from, against the front end face of the through hole 84 rests in the direction of the control chamber 62 as a projecting collar 92 extended and through the material of the housing base part 50 is trained.

As 7 reveals, at least in the direction of the circulation chamber 14 substantially cylindrically shaped outer peripheral surface of the heat sink 86 on opposite sides circumferentially of locking projections 94 surmounted, those with locking noses 96 , the inner circumference of the substantially cylindrical passage opening 84 Overhang, cooperate to form a bayonet closure through which the heat sink 86 opposite the housing base part 50 is fixed. The sealing ring 88 can be designed so that it holds this lock under axial and / or radial bias. In addition, the control chamber floor 84 adjacent to the mouth in the through hole 84 on the side of the circulation chamber 14 be provided with depressions, in which the locking projections 94 intervene and the the heat sink 86 positively secured against rotation, to prevent unintentional loosening of the bayonet closure 94 . 96 to prevent.

The 7 Gives the look in through the control chamber floor 64 and the walls 60 formed control housing pan, which is closed in the final assembled state by the cover 72.

The 5 shows above the partition 54 one through the partition 54 and the walls 58 formed connecting trough 100 , On the following in the presentation 5 underlying page is through the housing base part 50 one through the partition 54 and the walls 52 formed circulation tub 102 formed. This is how the housing base part forms 50 essentially all chambers 14 . 56 . 52 only by the cover elements 72 . 80 . 82 must be covered in order to create a functional and designed as a lightweight plastic component electrical heating device.

Sealing over-molded busbar

The 8th illustrates a busbar 104 acting as electrical conduction path between the connection chamber 56 and the control chamber 62 is provided. At the level of the control chamber floor 64 and within it is the bus bar 104 two turns in opposite directions by 90 °. One inside the control chamber 62 located end of the busbar 104 is as a plug-in connection for a provided inside the control chamber assembled printed circuit board 106 trained (cf. 6 ). The other end is inside the connection chamber as a connection tongue 108 for a provided within the connection chamber and omitted in the previous figures distributor plate. The distributor plate can according to EP 2 505 931 A1 be educated. By several consecutively provided in an identical manner busbars 104 lie several connection tongues 108 within the connection chamber 56 free. The connection tongues 108 extend parallel to the reeds 42 to the PTC Heating elements. Thus, the distributor plate for contacting with all contact or terminal tongues 42 . 108 be sunk into the connection chamber from above.

shielding

The metal strips 128 are formed from stamped sheets and represent embodiments of contact plates.

The 9 shows a partially sectioned view of the housing described above 2 , This plastic housing 2 is through two metal shells 110 . 112 surround, which form a shield of the electric heater, so that electromagnetic radiation can not be discontinued from this. The division plane of the metal shells 110 . 112 is located approximately at mid-height of the two nozzles 6 . 8th , The metal bowls 110 . 112 surround the case 2 essentially in full. Only on the plastic housing 2 trained fastening projections 114 protrude through the metal shells 110 . 112 trained recesses 115 over the metal shells 110 . 112 and the shield formed thereby to the outside. Furthermore surmount by reference numerals 116 respectively. 118 characterized connector housing, wherein the connector housing 116 for the present high-voltage power and the connector housing 118 is provided for the operated with low voltage control lines. In the 9 shown embodiment allows the attachment of the housing 2 over the fastening elements formed of plastic 110 , With this can be easily met the requirement, the housing 2 to be fastened at the desired location within a motor vehicle. In 9 are the metal shells 110 . 112 essentially continuous. They can just as well be formed from a perforated plate without the effect of the metal shells 110 . 112 lost as EMC protection.

PTC heating element as a frame element

In 10 is a PTC element 120 shown, which at its mutually opposite main side surfaces 122 with an insulating layer 124 is occupied. The insulating layer 124 In this case, a ceramic plate made of aluminum oxide. It can also be used as a coating on the PTC element 120 be applied or be implemented as Kombinatino a coating with a single or multi-layer insulating layer. The PTC element 120 is formed as a small plate with a width B or a length L , which are larger by a factor of at least 10 than the thickness D , which is the distance between the two main side surfaces 122 equivalent. In essence, in the direction of the length L are extending on opposite end faces 126 each metal strip 128 provided with the PTC element 120 glued and electrically conductive to a surface metallization of the PTC element 128 , which may be applied as protection by means of PVD or CVD, are connected. These metal strips each form tracks of different polarities, with which the PTC element 120 is energized. The metal strips 12 consist of a contact bridge 130 which is relatively narrow and opposite the contact bridge 130 in the direction of the width B widened contact tongue 42.

The contact bridges 130 In the present case, the electrodes form the PTC element and are connected to the metallization of the PTC element 120 electrically connected. The thickness of the contact tongue 42 is less than the thickness of the contact bar 30 , Its thickness is again smaller than the thickness D of the PTC element. The metal strip 128 is provided so that this at no point the main side surfaces 122 of the PTC element 120 surmounted. As the 11 and 12 in particular can be seen, protrude the insulating layers 124 laterally beyond the PTC element 120. The insulating layers 124 have demensprechend a footprint that is larger than the base of the main side surfaces 122 of the PTC element 120 is. Accordingly, the outer edges of the insulating layers take 124 on both sides of the contact bridge 130 between themselves (cf. 12 ). Every contact bridge 130 is glued to one of the opposite end faces 126. The insulating layer 124 is also with the PTC element 120 bonded. The insulating layer 124 is directly on the PTC element. So contacted one of the insulating layers 124 the associated main side surface 122 of the PTC element immediately.

The outside of the respective metal strips 128 is perfectly flat and stretches strictly in the direction of the length L , The tongues 42 are larger in the width direction than the contact bridge 130 formed and project beyond the PTC element 120 towards each other (cf. 10 ). The contact tongue 42 is also thinner than the contact bridge 130 ,

The opposite the contact bridge 130 widened area of the sheet metal strip 128 is in a heating element housing 134 taken, which frame the PTC element 120 surrounds. This plastic frame 134 closes the peripheral edges of the insulating layers 124 one. Also the border areas 132 are of the plastic frame 134 sealed plastic material. The plastic frame 134 is by encapsulating an elastomeric material as an elastomeric plastic frame 134 educated. In the finished PTC heating element 40 only exceed the reeds 42 on one end the plastic frame 134 , All other functional parts of the PTC heating element used for heat generation and power supply 40 are inside the plastic frame 134 added. In particular 12 clarifies, lies the PTC element 120 with its opposite main side surfaces 122 behind with reference numerals 136 marked and through the plastic frame 134 formed frame openings. These frame openings 136 are covered by the insulating layer 124 , In the present case there is almost no overlap of the plastic frame 134 with the main side surfaces 122 of the PTC element, so that this to approximately 100% of its major side surfaces 122 behind the frame openings 136 exposed.

The right angle of the sealing collar 48 projecting frame rail of the plastic frame 134 are each with peripheral system webs 137 Mistake. The plant webs 137 are designed in the manner of tapered fins, which is one opposite the thickness of the plastic frame 134 have tapered thickness. How, for example, on 6 can be seen, are the PTC heating element 40 each one behind the other slightly offset, so that each first PTC heating element 40 on the left side on a wall of the housing 2 abuts and there over the sealing against a boundary wall of the circulation chamber 14 adjoining landing stage 137 are sealed. So on this page no fluid on the PTC element 40 flow past, but probably on the upstream or downstream lying in the flow direction PTC heating element. This in turn lies with his investment jetty 137 on the opposite side to the circulation chamber 14 wall and laying the flow channel there. This is done by alternately arranging the PTC heating elements 40 formed a meandering flow channel.

connector

The plastic frame 132 also forms the previously described sealing collar 48 out, with to the free end of the reeds 42 tapered segments 138 is provided (see. 13 ). Here are three of these segments 138 in the longitudinal extension direction of the contact tongue 42 provided one behind the other. Between the frame opening 136 and these segments 138 is an annular stop 140 through the heater housing 134 educated. As 13 clarifies, this stop is sealing against a cylindrical and through the female plug element receptacle 44 formed counter surface 142 at.

As the 2 and 5 clarify, lies the opposite side of the PTC elements 40 after installation on the floor 18 of the housing 2 at. For accurate positioning are in the ground 18 wells 144 provided, in which the end faces of the Heizelementgehäuses 134 are included. This will result in an exactly right-angled positioning of the PTC heating elements 40 relative to the partition 54 guaranteed. Furthermore, a holding force is generated, which prevents that in the partition 54 Plug-in PTC heating elements 40 during operation and in particular due to the vibration of the vehicle from the female plug element receptacles 44 can fall out. This bottom-side installation of the PTC heating elements 40 also ensures the contact pressure within the plug contact of the PTC heating elements, so that these safe and durable, the longitudinal slots 46 to the connection chamber 56 caulk.

It goes without saying that on the depressions 144 can also be dispensed with. Similar to the plant webs 137 can also be attached to the sealing collar 48 opposite underside of the plastic frame 134 a jetty 137 be provided, which is under elastic compression against the ground 18 of the housing 2 supports and seals there. This will not only provide a fluid tight seal between the underside of the PTC heating element 40 and the housing 2 created. Rather, by the compression of the contact bar also generates a compressive force, which the PTC-Heizlement 40 also captive in the female plug element receptacle 44 stops when strong vibrations act on the electric heater.

Electrical connection of the PTC heating elements

The 14 - 16 illustrate the electrical connection of the PTC heating elements 40 the example of another embodiment. It shows 15 the embodiment without the housing 2 and parts of it, similar to the representation in 3 , For the electrical connection are in the connection chamber 56 stamped sheets as busbars 146 . 148 . 150 provided, the formed by punching and bending contact protrusions 152 have, under elastic bias against the reeds 42 contact and contact them. The contact projections 152 protrude into receiving openings 154 into it, in the metal strips of the busbars 146 . 148 . 150 are omitted. The with reference numerals 148 characterized busbar has a corresponding receiving opening 154 with contact tabs 152 for the busbar 104 , The with reference numerals 146 respectively. 148 marked busbars are each with a power transistor 156 equipped, the electrically conductive with the corresponding busbar 146 . 150 connected and mounted on it. The power transistors 156 are input side with also designed as a busbars Zuleitern 158 connected, in turn, receiving openings 154 with contact tabs 152 for contacting via one busbar each 104 are provided. Then the electrical conduction within the confinement chamber 56 solely by sheet metal elements. These sheet metal elements are exclusively with the power transistors 156 equipped as electrical or electronic components. There are no further electrical or electronic components provided.

In particular 16 clarified, these are metal plates 146 . 148 . 150 . 158 electrically insulated from each other in the connection chamber 56 used and positioned there. The on the circuit board 106 processed control signals for driving the power transistors 146 be about at least one of the Zuleiter 158 the respective power transistor 156 fed.

The 16 clarifies a sectional view at the height of one also in 15 with reference number 86 characterized heatsink. Between the heat sink 86 and the power transistor 156 is an electrical insulating layer 160 realized for example from Kapton or a ceramic plate. The between this insulating layer 160 and the power transistor 156 provided bus bar 146 . 150 leads to a certain spread of the power transistor 156 released heat. This can be the busbar 146 respectively. 150 at least in the area of the power transistor 156 be formed with a greater thickness. It is equally possible to use the busbar 146 respectively. 150 made of copper and thus a thermally conductive material auszuformen. The sheet material may be in the range of the power transistor 156 by contour rolling has an increased thickness.

The busbars 146 . 148 . 150 . 158 can be provided by punching with a Crimplasche or the like, with the housing 2 interacts with the respective busbar 146 . 148 . 150 . 158 on the housing 2 attach and / or the power transistor 146 under bias against the heat sink 86 create or press.

The 16 also leaves a variant of the PTC heating element 40 detect. After that are the reeds 42 inside the plastic frame 134 in a fastening plug formed from a hard plastic component 162 added. The tongues 42 are by molding in the mounting plug 162 added. The mounting plug 162 is made of a hard plastic with good creepage and dielectric strength. The fixing plug 162 forms a hard core for that through the PTC heating element 40 formed male plug element. This fixing plug 162 is only by a thin coating of the soft elastic material of the sealing collar 48 coated, which through the sealing collar 48 formed compressive force within the female plug element receptacle 44 is increased. The fixing plug 162 For example, by molding two metal strips 128 carried out, each for themselves the contact webs 130 and the contacts 42 molding as a one-piece component. Prepared in this way and spatially and physically positioned relative to each other, the fastening plug 162 along with the metal strip 128 as previously described with the soft elastic plastic component for forming the plastic frame 134 to be overmolded.

Also with the variant after the 14 - 16 the sealing collar is elongated. It goes without saying, however, that every single contact tongue 42 can be arranged in a cylindrical sealing collar with a basically circular or oval cross-sectional area. The female plug element holder 44 is then also provided with a circular or oval cross-section. Such a configuration can increase the tightness compared to the concrete embodiment described. It goes without saying that even polygonal cross-sectional areas are possible.

16 also allows the attachment of the heat sink 86 inside the partition 54 detect. The heat sink 86 has at the height of the partition 54 on its outer periphery a heat sink 86 on the edge superior mounting collar 164 by spraying the separator 54 forming plastic material is positively sealed. The embodiment of the fastening collar 164 Incidentally, improves the tightness between the circulation chamber 14 and the connection chamber 56 ,

According to a variant, not shown, the to the connection chamber 56 protruding surface of the heat sink 86 also from the partition 54 be formed plastic material. When overmolding the heat sink 46 For example, a thin film can be injection molded between the surface of the heat sink 86 and the interior of the connection chamber 56, via which the power transistor 156 on the heat sink 68 electrically isolated. As a result, the production is further simplified. A separate electrical insulation layer does not have to be between the power transistor 156 and the heat sink 86 be provided.

LIST OF REFERENCE NUMBERS

2

casing

4

When the housing element

6

inlet port

8th

outlet

10

inlet port

12

outlet

14

circulation chamber

16

heating chamber

18

ground

20

partition wall

22

cover

24

partition wall

26

connecting channel

28

Channel wall segment

30

Channel wall segment

32

edge

34

groove

40

PTC heating element

42

contact tongue

44

female plug element holder

46

longitudinal slot

48

sealing collar

50

Housing base part

52

wall

54

partition wall

56

terminal chamber

58

wall

60

wall

62

control chamber

64

Control chamber floor

66

Groove of the circulation chamber 14

68

Groove of the connection chamber 56

70

Groove of the control chamber 62

72

Cover member to the control chamber 62nd

74

wreath

76

counter-groove

78

inner jetty

80

Housing cover to the circulation chamber

82

Housing cover to the connection chamber

84

Through opening

86

heatsink

88

seal

90

attack

92

collar

94

locking projection

96

locking tab

98

control pan

100

connection tub

102

circulation bath

104

conductor rail

106

circuit board

108

terminal blade

110

metal bowl

112

metal bowl

114

fixing projection

115

recess

116

Plug housing high voltage

118

Connector housing low-voltage

120

PTC element

122

Major side surface

124

insulating

126

Front side surface

128

metal strip

130

contact web

132

edge surface

134

Heater housing / plastic frame

136

frame opening

137

mooring facilities

138

segment

140

attack

142

counter surface

144

deepening

146

conductor rail

148

conductor rail

150

conductor rail

152

contact projection

154

receiving opening

156

power transistor

158

feeders

160

insulating

162

mounting plugs

164

fixing collar

B

Width of the PTC element

L

Length of the PTC element

D

Thickness of the PTC element

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2607121 A1 [0001, 0008, 0017, 0025, 0063]
• EP 1253808 A1 [0002]
• EP 1395098 A1 [0002]
• EP 2797381 A1 [0016, 0043, 0077]
• EP 2440004 A1 [0018]
• EP 1921896 A1 [0018]
• EP 1768459 A1 [0041, 0076]
• EP 1872986 A1 [0041, 0076]
• EP 2505931 [0047]
• EP 2505931 A1 [0060, 0081, 0105]

Claims (7)

PTC heating element (40) with a Heizelementgehäuse (134), the at least one PTC element (120) and the PTC element (120) energizing and contact tongues (42) for an electrical connector forming contact plates (128) for the electrical connection of electrically connected to the PTC element (120) connected electrodes (130) as a structural unit, wherein the PTC element (120) at least at one of its two major side surfaces (122) covered with an insulating layer (124), characterized in that the Heater housing has an injection-molded plastic frame (134) which surrounds the insulation plate (124) only edge and defines opposite frame openings (136), behind which exposes the PTC element (120) with its main side surfaces (122). PTC heating element (40) after Claim 1 , characterized in that the insulating layer (124) directly on the PTC element (120) rests or is provided thereon. PTC heating element (40) after Claim 1 or 2 , characterized in that the two main side surfaces (122) of the PTC element (120) each having an insulating layer (120) are covered and that the two insulating plates (120) in the opposite frame openings (136) is exposed. PTC heating element (40) according to one of the preceding claims, characterized in that the PTC element (120) and the at least one insulating layer (120) by encapsulation of the plastic frame (134) forming material with the plastic frame (134) are connected. PTC heating element (40) according to one of the preceding claims, characterized in that the plastic frame (134) forming material is an elastomeric plastic. PTC heating element (40) according to one of the preceding claims, characterized in that the contact tongue (42) by a metal strip (128) is formed, which has an end face on the PTC element (120) electrically conductive contact web (130) and that the plastic frame (134) forms the outer peripheral surface of the PTC heating element (40), is surmounted only on one end side by the two contact tongues (42). PTC heating element (40) according to one of the preceding claims, characterized in that the plastic frame (134) is provided on its outer side with a tapered abutment web (137).

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